That's funny. Yesterday was the first time that I actually wished I had one in the shop. I was doing some edgebanding, by hand, on some fairly small parts that had curved edges. They were too small to clamp from the surface and the curve going around a 90 angle made it impossible to clamp from the edges.
I ended up making a fixture to hold a MFK700 upside-down and stationary. This way I could move the parts over the tool, instead of the usual.
There have been other times when it would have been handy, but a work-around wasn't so big of a deal either. This time, it took as long to build the fixture as I actually needed to use it, but I will have it for future use, so not a big loss either.
Still would be nice to have a Vac-Sys though.